diff --git a/libraries/app/application.cpp b/libraries/app/application.cpp
index 9cf07b01..07ac83de 100644
--- a/libraries/app/application.cpp
+++ b/libraries/app/application.cpp
@@ -844,6 +844,9 @@ namespace detail {
               return synopsis; // we have no blocks
           }
 
+          if( low_block_num == 0)
+             low_block_num = 1;
+
           // at this point:
           // low_block_num is the block before the first block we can undo,
           // non_fork_high_block_num is the block before the fork (if the peer is on a fork, or otherwise it is the same as high_block_num)